A navigation system performs travel guidance for enabling a user to easily and quickly reach the selected destination. A typical example is a vehicle navigation system where a navigation system is installed in a vehicle such as an automobile, boat, bicycle, and the like. The present invention is not limited to a vehicle navigation system but is applicable to other types of navigation systems such as a PDA (personal Data Assistant), a cellular phone, and other portable navigation devices. However, for the convenience of explanation, the following description is made mainly for the vehicle navigation system.
Such a navigation system detects the position of the vehicle, reads out map data pertaining to an area at the current position of the vehicle from a storage medium, for example, a CD-ROM (compact disk read-only memory) or a DVD (digital versatile disc), and displays a map image on a monitor screen (display) while superposing a mark representing the current location of the vehicle on a predetermined portion of the map image. Alternatively, such map data can be provided to the user's navigation system from a remote navigation server through a communication network such as an Internet.
When a destination is set, the navigation system starts a route guidance function for guiding the user through a guided route from the start point to the destination. To determine the guided route to the destination, the navigation system calculates and determines an optimum route to the destination based on various parameters. During the route guidance, when the vehicle is within a predetermined distance of an intersection it is approaching, an intersection guidance diagram is displayed to inform the user of the desired one of roads or directions selectable at the intersection. Such route guidance by the navigation system is also given by voice instructions.
FIGS. 1A–1H show an example of overall procedure and screen display involved in the navigation system. FIG. 1A shows an example of locator map screen of the navigation system typically used when the destination is not specified. The navigation system displays a street on which the vehicle (current vehicle position VP) is running on a map image and a name of the street. Other information such as a north pointer NP, a map scale and a current time may also be illustrated on the display screen.
FIGS. 1B–1F show an example of process for specifying a destination in the navigation system. When selecting a “Destination” menu on a main menu screen of FIG. 1B, the navigation system displays an “Find Destination By” screen as shown in FIG. 1C for specifying an input method for selecting the destination. The “Find Destination By” screen lists various methods for selecting the destination, which include “Address”, “Intersection”, “Point of Interest (POI)”, “Recent Route”, “Address Book”, and “Today's Plan”.
The input method “Today's Plan” is to specify two or more destinations in the navigation system and is directly related to the present invention. When selecting the “Today's Plan” method in FIG. 1C, the navigation system displays a keyboard screen in FIG. 1D. Suppose the user inputs an address or a place name of the destination, the navigation system displays a “Confirm Destination” screen such as shown in FIG. 1E. If the name and address on the screen shows the correct destination, the user enters an “OK to Proceed” key to proceed to the next procedure.
In FIG. 1F, the navigation system calculates and determines a route to the destination, i.e., the address “2525 W. Carson”. The navigation system determines a route to the destination based on, for example, the quickest way to reach the destination, the route using many free ways as possible or the route without using toll road, and the like. Since the “Today's Plan” method allows the user to input two or more destinations, the foregoing procedure for specifying a destination and calculating the route to the destination will be repeated.
Once the route to the destination is determined, the navigation system starts the route guidance as shown in FIG. 1G for guiding the user to the destination. Typically, the navigation system shows an intersection that is highlighted on the display to show the next turn and a direction of the turn. When the user approaches the destination with such a predetermined distance, the navigation system indicates that the destination is ahead as shown in FIG. 1H. The navigation system detects the actual arrival at the destination based on various factors such as stop of the engine.
As in the above example, when the “Today's Plan” method is selected in FIG. 1C, the user can input a plurality of destinations that will be visited during the course of the day as shown in FIG. 2A. Then the navigation system calculates an efficient order and route to those destinations. For example, to determine the next destination and its route, the navigation system seeks a next destination that is located at the shortest distance from the current destination (considering not only a physical distance but also a time and fees, i.e., an overall cost). In the example of FIG. 2A, the user planed to visit the destinations A–G within a day.
However there are often times when a user cannot visit all of the destinations in the list. In FIG. 2A, the user finished visiting the destinations A–D on that day, however, destinations E, F and G are unfinished by the end of the day. Typically, when a user could not arrive at all of his destinations, the navigation system stores the remaining destinations in its memory so that it could be used in the future. Thus, on the next day, when the user inputs new destinations H, I and J, destinations stored in the navigation system are both the unfinished destinations E–G and the new destinations H–J as shown in FIG. 2B.
Accordingly, the navigation system asks the user to confirm the destination E which is unfinished yesterday as shown in FIG. 2C and starts route calculation as shown in FIG. 2D. The navigation system guides the user to the destination E, and detects the arrival at the destination E as shown in FIG. 2E. Then, as shown in FIG. 2F, the navigation system repeats the above procedure for the next unfinished destination F and G.
This seemingly useful feature creates confusion often times because whenever the user goes back to the list, the previous destinations still exist in the navigation system as a list of “Today's Plan” even when the user no longer interested in going to those destinations. Then the user has to erase all of the unwanted destinations on the list before or after inputting new destinations. Typically, when erasing such unwanted destinations from the destination list, the user has to go through series of key strokes and scrolling, which is time consuming.
Therefore, there is a need for a navigation system which is able to update the list of destinations to avoid confusion by the user in the “Today's Plan” mode. There is a need for a navigation system that can provide the user with an easy way to choose which destinations are still desired to be remained in the navigation system so that a new list containing old destinations and new destinations can all be processed. Not only in the “Today's Plan” method, but also there is a need in a normal mode, where only one destination is set, that the navigation system provides means to choose whether to delete or renew the unfinished destination.